1. Field of the Invention
The present invention relates to an acoustic convection apparatus for use in a system where uniform distribution of heat and density is needed and to a convective cooling at apparatus for cooling heat-generating components in electronic or electrical devices.
2. Description of the Related Art
As electronic devices become more complex and highly integrated, much effort has been made to improve the performance of apparatus for cooling such devices. To enhance the ability to dissipate heat from an electronic devices, such as computers or communication equipments, which contain many heat-generating components, heat should be forcibly transferred from the components to the surrounding cooling medium. As the electronic devices become more compact, passages of the cooling medium become narrower, thereby slowing the flow of the cooling medium. Moreover, in narrow passages, there exists only laminar flow without eddies. With the laminar flow, the cooling fluid is not actively mixed, which in turn prevents efficient convective heat transfer from the components to the cooling medium.
There have been several attempts to solve this problem. One of them is so called forced convection, which is to increase the velocity of the cooling medium by using a cooling fan or a pump. As the heat generation from the electronic components increases, the air flow rate should be increased by using a high powered fan or a pump. However, such a cooling system induces high power consumption and noise. Moreover, a fan or a pump cannot be easily used in very small devices.
Another approach is to shift the movement of the fluid from laminar to turbulent flow by adding turbulence-inducing material. However, these methods may suffer from noise and low reliance. The fan used for the cooling application is also being employed to enhance fluid mixing in thermal systems such as an oven, a furnace, a drying machine or a refrigerator. Air flow generated from the fan makes the distribution of temperature or density uniform to a certain degree. However, such a system also shows low efficiency because the air flow may not be uniform.
An object of the present invention is therefore to provide a convection apparatus which reduces the nonuniformity of air flow in a space where uniform distribution of temperature and density is needed, thereby improving the efficiency of an overall system disposed in the space.
Another object of the present invention is to provide a convective cooling apparatus for effective heat dissipation from electronic devices, which are compact and light-weighted.
In accordance with an aspect of the present invention, there is provided a convection apparatus for providing convective flow of medium in a system, which comprises a driver for generating a driving signal with a predetermined frequency and a vibrator, in response to the driving signal, for generating acoustic waves to an interior of said system.
In accordance with another aspect of the present invention, there is provided a convective cooling apparatus for cooling an electronic device including at least one heat-generating component and enclosed in a case having cooling medium therein. The convective cooling apparatus of the present invention neither attempts to increase the velocity of flow in the cooling fluid nor replaces the cooling medium with other material as prior art cooling apparatus did. Instead, it utilizes the hydraulic instability which is inherent in the flow of the cooling medium. In the convective cooling apparatus of the present invention, by using a driver for generating a signal tuned to a characteristic frequency of flow, an acoustic vibrator is driven to provide acoustic waves. The acoustic waves induce resonance in flow, which renders the cooling fluid vigorously mixed, which, in turn, enhances the heat dissipation from the device.